Tinsley, who was 45, commanded Elmendorf Air Force Base in Anchorage, Alaska, and was still flying F-22s when he shot himself in the chest one afternoon in an uncharacteristic outburst of rage.

In a lengthy interview with the Star-Telegram, Joanna Tinsley said her husband experienced big changes during the last few months of his life. He was normally a happy, highly energetic and caring man, but he deteriorated physically and emotionally.

"He was short-tempered. He was impatient. He would get mad at things that never would have agitated him before," said Tinsley, who now lives in Phoenix.

"He was more foggy-headed. He would ask questions over and over again and then stare at you with a blank look."

Tinsley suffered headaches, his appetite diminished, and he had trouble sleeping. He was plagued by a chronic cough, a common problem for F-22 pilots.

Now, after reading reports of strange occurrences involving other F-22 pilots and comparing notes with other wives, Tinsley said she can't help but believe that the Air Force's prized fighter is a health risk. Something about the F-22, she theorizes, may have triggered her husband's suicide.

"They're seeing the same things, the same changes that I saw in Tom," Tinsley said.

Tinsley, another wife and two former engineers who worked on the plane's development are among those who believe that something still isn't right with the F-22, which was partially built at Lockheed Martin's Fort Worth plant.

Reassuring statements aside, they said, the fighter's problems haven't been fixed and are worse than the Air Force lets on.

Numerous reports over the past four-plus years described F-22 pilots as becoming disoriented, even blacking out in flight. A lingering cough and respiratory problems were commonly reported, as well as neurological and emotional problems. Two pilots were killed in F-22 crashes.

Amid growing evidence of issues not seen in earlier fighter jets, and facing congressional pressures, the Air Force launched an investigation in 2011. The planes were grounded for several months.

Air Force accident investigators found that the pilot in one crash apparently became disoriented and was unaware of impending danger until it was too late. In another case, the aircraft's air-supply system failed and the pilot did not or could not activate his emergency oxygen supply, became disoriented and made no attempt to right his plane for 31 seconds before crashing into frozen Alaskan soil.

Other pilots have landed safely but with no memory of doing so. One flew through treetops on approach and apparently didn't know it.

The F-22, jointly developed and built by Lockheed Martin and Boeing, is the Air Force's most prized warplane.

The jet, which costs an average of $412 million, including research and development, is advertised to be nearly invisible to radar. It can fly faster than the speed of sound for long periods and can maneuver and fight at higher altitudes than older fighters.

In an Aug. 1 Pentagon news briefing, Maj. Gen. Charles Lyon said that the Air Force had conducted a months-long investigation of the problems and symptoms reported by F-22 pilots. The Air Force believes that it has solutions in place and has briefed the pilots, who, Lyon said, are gung-ho to fly the planes.

"We've explained all of this. We've had a lot of ongoing dialogue with them, and what I want you to know is that both they and their families have very high confidence in the F-22," Lyon said.

But not everyone is on board. The wife of one longtime F-22 pilot told the Star-Telegram that her husband and others remain unconvinced by Air Force assurances that the problems are understood and that the plane is safe to fly.

The woman, who asked to remain anonymous because her husband is an active-duty officer, said that she, too, has seen disturbing changes over time. They include a chronic cough, impaired motor skills, loss of concentration and an inability to recall words and facts, as well as lethargy and "crushing headaches."

The symptoms improved last year when the planes were grounded as part of the Air Force investigation, she said.

"I'm concerned. He's concerned. And he's not alone," she said.

Both Tinsley and the other wife said they decided to speak out after the Air Force's vote of confidence in the F-22, and also after two pilots put their careers on the line by refusing to fly the plane and appearing on 60 Minutes in May.

'Nothing remarkable'

Several theories have been offered about the mysterious problems, but no firm answers. Some blame the system that provides filtered air to the pilots for breathing, or the air that pressurizes the cockpit.

Others suspect that toxic substances are entering the air supplies, either from the F-22's top-secret stealth coatings or perhaps from oils and fluids in the power and hydraulics systems.

Lyon said at the news briefing that the Air Force investigation, which included medical and physiological testing of pilots and blood and air samples, "eliminated contamination as a contributing factor to these incidents."

"We found nothing remarkable."

Neither Lockheed Martin nor Boeing would comment specifically on the health concerns associated with the F-22, referring questions to the Air Force. Lockheed built the fighter's midfuselage at its Fort Worth plant.

Joe Stout, a Lockheed spokesman in Fort Worth, said the company "has and continues to support the U.S. Air Force's requirements to ensure the F-22 meets their expectations on availability, performance and reliability."

Lockheed and Boeing recently settled a liability lawsuit filed by Anna Haney, the wife of Capt. Jeff Haney, who died in a Nov. 16, 2010, crash in Alaska. Terms of the settlement were not disclosed.

The Air Force's investigation turned up "no smoking gun" to explain the repeated incidents of disorientation, described as hypoxia-like events that suggest pilots aren't getting enough air. Instead, Lyon said, there were "pieces of a mosaic," or several contributing problems.

The primary culprit, he said, was an air valve that controls the inflation of a pressure vest. The pilots wear the vest to combat blood drain experienced during high-G-force maneuvers. Because of the design of the F-22's oxygen system, the vest was inflating too early in flight, putting added pressure on pilots' chests and restricting their breathing.

The valves are being redesigned and, if they work as expected, will be incorporated into new vests.

Until then, the F-22 is cleared for flying but not at the 50,000-foot-plus altitudes where it's supposed to operate. If war broke out, pilots would have to fly wearing the current vests.

The Air Force also said the air-supply system may not, at times, provide enough oxygen because of leaky fittings and a too-small hose, forcing pilots to work too hard to breathe. Those components will be fixed as well.

As for other symptoms, including breathing problems reported by F-22 ground crews, Lyon said those could be due to hypoglycemia or dehydration. Pilots will be instructed to eat better and get plenty of fluids before flying.

A dozen F-22s were recently deployed to Japan and made the long trans-Pacific flights with no reported problems.

There has not been "an unexplained incident" in which a pilot reported breathing problems or disorientation in more than 8,000 flights and 10,000 flight hours, Lyon said at the briefing.

But as recently as June, a pilot landed at Langley Air Force Base in Virginia and pulled his emergency oxygen supply handle because of breathing "discomfort."

The Air Force said that and another recent incident were due to "mechanical problems" with the air supply.

'Welcome to the Raptor'

The Air Force's explanations do not satisfy Kevin Divers, a former F-22 flight test engineer and physiology expert who was deeply involved in early testing of the F-22's life-support system.

As far back as 2000, Divers said, the Air Force tests showed that the pressure vest was filling up, but pilots didn't complain that it was a problem.

"At first we put it down as an annoyance" based on the advice of physiologists, said Divers, who lives near Nashville. "We told the pilots, 'Welcome to the Raptor.'"

The Air Force says most reports of pilot disorientation have come since 2010. Divers, who left the service in 2007, said he's heard from concerned pilots since at least 2008.

Divers said he's pretty sure that a lack of oxygen is not the problem. Too much or, more accurately, too high a concentration of oxygen too soon is a more likely explanation for most symptoms that pilots have reported to him, he said.

The F-22, conceived during the Cold War to fight the Soviets, was designed to provide the pilot with pressurized, highly oxygenated air in case chemical or biological weapons were used. It's unlike any previous fighter jet.

Normal air contains about 21 percent oxygen. The moment F-22 pilots strap on their air masks, they're breathing 60 percent oxygen. Within the seconds it takes the plane to reach 11,000 feet after takeoff, the pilot is breathing air that's 93 percent oxygen.

But that's far more than the body needs except at the highest altitudes and in high-G-force maneuvers, some experts say.

As the aircraft accelerates and the rich oxygen is forced into the lungs and can't be absorbed, it creates a condition called "acceleration atelectasis," in which alveoli, which transmit oxygen to the blood and remove carbon dioxide, collapse.

That causes breathing to become more labored as pilots maneuver at high speeds, with high G-forces hampering the blood supply. Their blood can't get rid of the carbon dioxide and can't get oxygen to the body's organs.

That could explain the disorientation and dizziness reported by pilots. It's almost like being intoxicated.

"If you get enough of that, you could certainly pass out," said Paul McDonough, an associate professor of kinesiology at the University of Texas at Arlington.

Recovery takes time, McDonough said. The post-flight "Raptor cough" is a sign of the body's attempt to reinflate the lung tissue and adjust to normal air pressure and oxygen level.

Little research has been done on the effects of repeated episodes of acceleration atelectasis, McDonough said. "The more exposure you get, the more symptoms you would see."

An Air Force medical officer downplayed the problem.

"I'm 100 percent convinced we do have acceleration atelectasis in the Raptor ... but it clears up in a matter of minutes or hours," said Lt. Col. Jay Flottmann, chief of flight safety for the 325th Fighter Wing at Tyndall Air Force Base, Fla., the training base for new F-22 pilots.

Flottmann is a physician and a qualified F-22 pilot and was involved in much of the work for the life-support-system investigation.

He said that during flights he conducted for the investigation, he, too, suffered breathing discomfort but that it quickly subsided after landing.

Breathing bad air?

Another theory involves toxic fumes, although the Air Force says it has found no evidence to support it.

One former Lockheed Martin engineer who worked on the F-22's development in Marietta, Ga., believes that chemical compounds sprayed on the aircraft to mask it from radar waves could be emitting toxic fumes that find their way into the breathing system and cockpit air.

Darrol Olsen, who lives in Claremore, Okla., spent the better part of two decades working on the Air Force's stealth jets, including Lockheed's F-117 and Northrop Grumman's B-2 bomber.

He was hired by Lockheed in 1995 to develop methods to repair the stealth coatings applied to the F-22. He said the work made him and other employees sick. He worked there until 1999, when he was fired.

"I had exactly the same problems the pilots have had," said Olsen, citing respiratory ailments, vertigo and sleeplessness.

Although the exact contents of the stealth coatings are among the tightest of U.S. military secrets, Olsen said tests showed that they contain diisocyanates, a group of chemical compounds commonly used in paint and plastics manufacturing. Diisocyanates can be toxic if improperly handled and breathed or touched, with respiratory problems a common symptom.

The toxicity question has merit, said former Pentagon official and longtime critic Pierre Sprey, who had a major role in developing the F-16 and A-10 in the 1970s.

Sprey is looking into the F-22 issues as an unpaid consultant for the Project on Government Oversight and believes it's plausible that stealth coatings could cause health problems for pilots and ground crews.

Sprey said that based on his research, "everything says we're dealing with a fast-acting toxin" and that the diisocyanates, in particular, are known to cause respiratory problems.

The Air Force said its investigation into the F-22 problems found no evidence to support Sprey's theory.

"We have gone to efforts unparalleled with any Air Force aircraft to identify if there were any contaminants in the life-support system," Flottmann said.

Sen. Mark Warner, R-Va., has been a critic of the Air Force's handling of the F-22 problems. In a statement, Warner said he is "encouraged the Air Force now has dedicated resources and attention to the recurring problems with the F-22" and is waiting to see the results.

"I am troubled by more recent revelations that appear to indicate the concerns about the F-22 life-support system were documented years ago," Warner said.

Joanna Tinsley is still looking for answers. The Air Force investigation of Gen. Tinsley's death, citing unnamed witnesses, insinuated that he had a serious alcohol problem. Joanna Tinsley said that wasn't the case, although he had been drinking at a party with colleagues in the hours before he took his life.

Divers, the Air Force engineer who knew the general well, concurs with her assessment. "He's the last person I thought would kill himself."

Tinsley was often on the flight line working with F-22 mechanics, Divers said, which would have increased his exposure to any toxic materials.

Something was wrong with Tinsley's health, Divers and the general's wife say. Something they suspect was linked to the F-22 Raptor.